Musnad Abu Ya'la al-Mawsili 150:421

Muslim ibn Abi Muslim al-Jarmi narrated to us, 'Isa ibn Yunus narrated to us, from al-Awza'i, from 'Abd al-Rahman ibn al-Qasim, from his father, from 'Aishah, the Mother of the Believers: It was mentioned to her that some people say, "There is no ghusl (ritual bath) except from the water (i.e., ejaculation)." She said, "I and the Messenger of Allah, may Allah bless him and grant him peace, have done that, and we performed ghusl."